The invention is based on a wiper blade.
Known windshield wipers for motor vehicles have a wiper arm, which is constructed of a fastening part, fastened to a drive shaft; a hinge part connected to it via a toggle joint; and a wiper rod rigidly adjoining the hinge part. A wiper blade with a wiper strip is pivotably connected to the wiper arm and guided over a motor vehicle window; the hinge part and the wiper blade are embodied such that the wiper strip can adapt to a curvature of the motor vehicle window. A requisite contact pressure of the wiper strip on the motor vehicle window is achieved with at least one tension spring, which braces the fastening part and the hinge part jointly with the wiper rod, via the toggle joint.
The wiper strip comprises an elastomer, such as a natural or synthetic rubber, or ethylenepropylene. It has a head strip, which via a tilting rib located between two longitudinal grooves is joined to a wiper lip resting on the vehicle window. By means of the tilting rib, the wiper lip at the turning point of the wiper motion can fold over in the opposite direction, so that it always assumes a favorable positioning angle relative to the windshield. If the windshield wiper is actuated, the wiper strip with the wiper lip slides over the motor vehicle window, and it wears down from friction between the wiper lip and the windshield. Environmental factors also affect the wiper strip, such as temperature fluctuations, UV radiation, saltwater, exhaust gases, and so forth, which can lead to premature aging of the material and increased wear.
To assure that when a new motor vehicle is shipped the wiper strip is in perfect condition, it is known from German Patent DE 30 05 965 C2 to cover the wiper strip with a guard profile before the motor vehicle is put in preservative. The guard profile is not removed until the new motor vehicle, after the preservative is removed, is handed over to a buyer. The guard profile has two side cheeks extending in the longitudinal direction, on which shoulders are formed that engage the longitudinal grooves on both sides of the tilting rib of the wiper strip. To enable cleaning the vehicle window so that the motor vehicle can be maneuvered, if the vehicle window during temporary storage of the motor vehicle or in the sealing process and so forth becomes soiled or the view is obstructed by rain, the guard profile has a wiper lip on its outer contour. As a rule, the guard profile comprises a suitable plastic.
To fasten the guard profile in such a way that it cannot be lost from the wiper blade and to protect the wiper strip on its face end from environmental factors, it is also known to weld the guard profile on the face end. To that end, the guard profile is heated on the lateral face ends and pressed against a plate. This creates a plate of material that closes off the guard profile. Before mounting, only one face end can be welded. If the second face end is welded after the guard profile has been slipped onto the wiper strip, then the guard profile has to be cut open for unmounting, which destroys it so that it cannot be used again.
From German Patent Disclosure DE 44 10 446 A1, a similar guard profile is also known, which for axial securing to the wiper strip has inward-pointing evulsions in the extensions in the region of the face ends. The evulsions block a longitudinal displacement of the guard profile, and their height is dimensioned such that they cannot penetrate into the longitudinal grooves. They are produced by drawing, for instance by ball upsetting.
In the earlier German Patent Application DE 199 35 858.3, a guard profile is described which has inward-pointing protrusions on its ends that originate at the side cheeks and extend either as far as the opposite side cheek or form a gap from the side cheek that allows mounting on a wiper strip. The protrusions can be combined with other closures for the face ends, such as a cap or a welded face end. The guard profile is fixed axially to the wiper strip by the closures or protrusions.
According to the invention, the protrusions originate at one side cheek of the guard profile, and a first protrusion extends, near the outer face end of the guard profile, to close to the opposite side cheek of the guard profile, while a second protrusion near the inner face end forms a gap from the opposed side cheek, which gap allows mounting or unmounting of the guard profile in the longitudinal direction. The protrusions can be made quickly and simply, for instance in the case of metal guard profiles with a kind of tongs or plastic profiles with a heat source, especially an ultrasonic source by means of an ultrasound probe.
Upon a pivoting motion of the windshield wiper over a vehicle window, force components that are especially pronounced if the vehicle window is dry or quite dirty or in wiper systems with four-bar control or a reciprocating gear act on the guard profile in the axial direction. In a four-bar control or reciprocating gear, the pivoting motion of the windshield wiper has a reciprocating motion superimposed on it, in order to increase the size of the swept field. However, in that case, major forces are exerted axially on the wiper blade. These forces tend to displace the guard profile in the direction of the inner circle, that is, the inner face end, of the wiper blade. Depending on the magnitude of the axial forces, the closures on the outer face end of the guard profile, if they are suitable for unmounting, experience excessive pressure. As a consequence, the guard profile creeps inward. This severely impairs the outcome of wiping, and part of the wiper strip, which is to be protected, of the windshield wiper is laid bare.
The wiper blade of the invention has a guard rail, which on the outer face end is closed by a protrusion extending transversely to the opening; this protrusion originates at one side cheek and extends as far as the opposite side cheek of the guard profile. This closure does not allow mounting or unmounting. As a result, it is assured that even under major axial forces the guard profile cannot creep inward. Nevertheless, it can be mounted and unmounted via the inner face end that has less of a load on it, so that it can be re-used multiple times.
Expediently, the length of the protrusions decreases in the direction of a wiper lip that is provided on the outer contour of the guard profile. Thus the protrusions essentially follow the inner contour of the side cheeks, so that the first protrusion can closely adjoin the opposed side cheek, and the gap between the second protrusion and the opposed side cheek remains virtually constant in width. The second protrusion has an inclined chamfer relative to the mounting direction, which chamfer, in the mounting process orients the wiper lip of the wiper strip toward the gap. This greatly simplifies mounting of the guard profile. To make unmounting easier as well, the second protrusion has an inclined chamfer relative to the unmounting direction, which chamfer, in the unmounting process orients the wiper lip of the wiper strip toward the gap. Expediently, the chamfer operative in the mounting direction, with a cross-sectional plane forms a larger angle than the chamfer operative in the unmounting direction, since the chamfer operative in the unmounting direction must during wiping operation assure a secure fixation of the guard profile with respect to outward-acting axial forces.
To assure the correct mounting of the guard profile in an automated mounting apparatus as well, it is expedient that the first protrusions differ in form, in particular in cross section and/or longitudinal section, from the second protrusions. As a result, the inner and outer ends of the guard profile can be identified simply and reliably. Moreover, the various protrusions can each be provided on different side cheeks of the guard profile.
The protrusions can be made quickly and simply, for instance in the case of metal profiles with a kind of tongs and in plastic profiles with a heat source, in particular an ultrasonic source by means of an ultrasonic probe; advantageously, the first protrusions on the outer face end of the guard profile can be welded to the opposed side cheek. This enhances the strength and shape stability, in particular transversely to the side cheeks in the critical end region.